A science fair classic, a homemade volcano is not only a lesson on how two household items interact with each other, it can also be a cool way to stage an eruption. First, create the volcano scene by using paper mache, clay or dirt as the mountain. Leave an opening to place the ingredients inside. Next, place in a couple of spoonfuls of baking soda. Then add liquid dish soap and vinegar. The baking soda and the vinegar react together to create "lava," which will then drizzle down the sides of the volcano. As an extra touch, place red and yellow food coloring in the mix to make it appear like real molten lava.
Quicksand has been made famous by action movies and television series in which a hero desperately tries to get away before the sand engulfs him. Make your own "quicksand" by combining a cup of maize cornflour and a half cup of water in a large plastic container. Stir the mixture quickly. The "quicksand" becomes hard and you can punch or poke it. This experiment works because the cornflour grains cannot slide over each other, as there is not enough water between them.
Your children will have fun playing with their food in this carbonation and choreography-based science experiment. First, pour a glass of colorless soda (such as 7-Up or Sprite) and watch how the carbon dioxide bubbles rise up from the glass. Next, drop seven raisins into the same glass and observe how the raisins act. Continue watching for a few minutes until they start "dancing." Because they are denser than the liquid, the raisins first sink to the bottom. Once the soft drink releases carbon dioxide bubbles, the raisins rise to the top because of the change in buoyancy. The raisins ride on the bubbles to the top of the beverage. After the raisins reach the top, the bubble pops, and the raisins sink again. This will continue until the soda goes flat and all the carbonation has left the glass.
Give dirty pennies a new shine with a bath in vinegar and salt. First pour about a quarter-cup of white vinegar and a teaspoon of salt into a nonmetal bowl. Place five old pennies into the bowl. Count to 10, take out the pennies and rinse them in water. Then admire their newly acquired shine. This works because vinegar contains acetic acid, which reacts with the salt to remove copper oxide. Copper oxide causes the pennies to become dull as the metal oxidizes.